"In the first 10 years of someone's life, there is hardwiring of sexual arousals and then, at puberty, it sort of turns on," Schwartz said. "Then, over time, [the fetish] gets cemented through the repetition of masturbation to the arousing object and it becomes relatively permanent."
The permanency of an individual's fetish can sometimes be made worse by the Internet, a place where there is often a group or chat room dedicated to even the most outlandish sexual desires, he said.
"I treated a patient who would try to strangle somebody in order to get aroused; he went online and 25 people came back to him and shared pictures of themselves doing the same thing and the fetish became more normative," Schwartz said.
While some sexual variance can be healthy in a relationship, fetishes can become a problem when they interfere with the ability to enjoy intimate, interactive sexual activity, McCarthy said.
"A lot of women will say that when they have a partner with a fetish arousal, that he's not really there during sex," McCarthy said. "He's there physically but he's not really there."
But fetishes don't have to be permanent and are often treatable to the degree that the individual is able to go on and have a healthy sex life.
Schwartz said that when he treats patients with fetishes, he revisits the original trauma that triggered the fetish.
"By reactivating that original trauma and getting in that high susceptible state, we are able to change some of the core arousal patterns," Schwartz said. "You can begin to see where the arousal came in and, in the future, when it comes to your conscious mind, you think back to the traumatic event."
McCarthy, who described fetishes as a sort of "sexual heroin," said that they can be much like an addiction to drugs.
"People give up heroin because they realize it's really hurting their lives," he said. "What a person with a fetish has to understand is the value of intimate sex. While it won't be highly erotically charged, it will fit more into the reality of his life."